| Abstract: | Experiments were done to test the hypothesis that aggregation of human platelets induced by platelet activating factor (PAF) may be mediated by calmodulin-dependent processes. W-7 [N-(6-aminohexyl)-5-chloro-1-naphthalene sulfonamide], a potent calmodulin antagonist, caused dose-dependent inhibition of PAF induced aggregation of human platelets in vitro. The ED50 for W-7 was 51.5 +/- 9.5 microM (mean +/- SEM). This concentration is known to be platelet calmodulin-specific. These data are consistent with the hypothesis. |
